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| author | David Brownell <dbrownell@users.sourceforge.net> | 2009-03-31 12:26:10 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-06-15 21:44:40 -0700 |
| commit | def6f8b978618d50daaddb92331d398da9e141f1 (patch) | |
| tree | ac8de48477184a97fec8cd96fa932b6ca90bb177 /drivers | |
| parent | dc2f2b7505c195a6963fc07b549e269eee417261 (diff) | |
| download | kernel-crypto-def6f8b978618d50daaddb92331d398da9e141f1.tar.gz kernel-crypto-def6f8b978618d50daaddb92331d398da9e141f1.tar.xz kernel-crypto-def6f8b978618d50daaddb92331d398da9e141f1.zip | |
USB: twl4030-usb: fix minor reporting goofage
Fix a reporting glitch in the twl4030 USB transceiver code.
It wasn't properly distinguishing the two types of active
USB link: ID grounded, vs not. In the current code that
distinction doesn't much matter; in the future this bugfix
should help support better USB controller communications.
Provide a comment sorting out some of the cryptic bits of
the manual: different sections use different names for
key signals, and the register definitions don't help much
without the explanations and diagrams.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/otg/twl4030-usb.c | 26 |
1 files changed, 19 insertions, 7 deletions
diff --git a/drivers/usb/otg/twl4030-usb.c b/drivers/usb/otg/twl4030-usb.c index c34e63910ac..9e3e7a5c258 100644 --- a/drivers/usb/otg/twl4030-usb.c +++ b/drivers/usb/otg/twl4030-usb.c @@ -217,6 +217,7 @@ /* In module TWL4030_MODULE_PM_MASTER */ #define PROTECT_KEY 0x0E +#define STS_HW_CONDITIONS 0x0F /* In module TWL4030_MODULE_PM_RECEIVER */ #define VUSB_DEDICATED1 0x7D @@ -351,15 +352,26 @@ static enum linkstat twl4030_usb_linkstat(struct twl4030_usb *twl) int status; int linkstat = USB_LINK_UNKNOWN; - /* STS_HW_CONDITIONS */ - status = twl4030_readb(twl, TWL4030_MODULE_PM_MASTER, 0x0f); + /* + * For ID/VBUS sensing, see manual section 15.4.8 ... + * except when using only battery backup power, two + * comparators produce VBUS_PRES and ID_PRES signals, + * which don't match docs elsewhere. But ... BIT(7) + * and BIT(2) of STS_HW_CONDITIONS, respectively, do + * seem to match up. If either is true the USB_PRES + * signal is active, the OTG module is activated, and + * its interrupt may be raised (may wake the system). + */ + status = twl4030_readb(twl, TWL4030_MODULE_PM_MASTER, + STS_HW_CONDITIONS); if (status < 0) dev_err(twl->dev, "USB link status err %d\n", status); - else if (status & BIT(7)) - linkstat = USB_LINK_VBUS; - else if (status & BIT(2)) - linkstat = USB_LINK_ID; - else + else if (status & (BIT(7) | BIT(2))) { + if (status & BIT(2)) + linkstat = USB_LINK_ID; + else + linkstat = USB_LINK_VBUS; + } else linkstat = USB_LINK_NONE; dev_dbg(twl->dev, "HW_CONDITIONS 0x%02x/%d; link %d\n", |